Predictive Factors for Upgrading or Upstaging in Biopsy Gleason Score 6 Prostate Cancer

ABSTRACT

PURPOSE: Although biopsy Gleason score (GS) 6 prostate cancers are expected to demonstrate a more indolent clinical course than those with GS 7 or higher cancers, substantial proportion reveal upgrading or upstaging on final pathology. We investigated predictive factors of upstaging or upgrading after radical prostatectomy (RP) in biopsy GS 6 prostate cancers. MATERIALS AND METHODS: A total of 133 patients with biopsy GS 6 prostate cancer who underwent radical prostatectomy between March 2004 and March 2008 were reviewed. Patients were divided into 4 groups according to the number of positive biopsy core single positive core (group 1, n=53), 2 (group 2, n=29), 3-5 (group 3, n=39) and 6 or more cores (group 4, n=12). We investigated the value of preoperative variables (age, PSA, Clinical stage, number and laterality of positive core, maximal core length, maximal core percentage) in predicting GS upgrading or upstaging in final pathology. RESULTS: Among all subjects, 70 (52.6%) were upgraded to GS 7 or higher and 29 (21.8%) were upstaged to pT3 at final pathology. Upgrading rates were 39.6%, 55.2%, 56.4% and 91.7%, and upstaging rates were 13.2%, 13.8%, 28.2% and 58.3% for groups 1, 2, 3 and 4, respectively. The upgrading and upstaging rates were similar among groups 1, 2 and 3, but were significantly higher in group 4 compared to the others. In multivariate analysis, number of positive cores 6 or more was the only factor significantly predictive of upgrading or upstaging following RP. No preoperative variables were observed to predict upgrading or upstaging following RP in patients with 5 or less positive biopsy cores. CONCLUSIONS: Of patients with only one or 2 positive core GS 6 prostate cancers, substantial proportion of cancers upgraded or upstaged in RP specimens, but no predictive factor could be identified. We should keep in mind these when counseling patients.